US EPA unveils plan to repeal power plant mercury, carbon emission standards

The US Environmental Protection Agency on June 11 announced plans to roll back all prior greenhouse gas limits for US power plants under the Clean Air Act, arguing that emissions from fossil-fuel-fired generation sources "do not contribute significantly to dangerous air pollution" under the air quality law.

The proposed rule, as worded, sets the stage for a repeal of the agency's landmark 2009 endangerment finding that underpins all US regulations of greenhouse gases. The EPA also announced a rulemaking to remove a 2024 Biden-era update to the nation's mercury standards for coal plants — a repeal that lignite coal producers had sought.

The power industry welcomed the measures, while health and environmental groups said a rollback of the air quality standards would jeopardize the health of millions of Americans.

The National Rural Electric Cooperative Association said in a statement that the now-targeted rules "force power plants into premature retirement and handcuff how often new natural gas plants can run," threatening energy reliability. The Edison Electric Institute, representing investor-owned electric utilities, said that it continues to support the EPA's authority to regulate greenhouse gas emissions under the Clean Air Act, while praising the elimination of carbon capture technology mandates for new natural gas-fired power plants.

"Electric companies need standards for natural gas facilities that are attainable to plan and permit new facilities, along with flexible regulatory approaches that help maintain dispatchable generation," EEI said.

The policy shifts come as the Trump administration attempts to boost declining US coal production and coal-fired generation. A November 2024 S&P Global Commodity Insights analysis found that utilities plan to shutter 61 GW of coal-fired power plants between 2025 and 2030 -- equal to more than one-third of the coal capacity online in 2024. On April 8, Trump signed four executive orders to lift barriers to coal mining and promote the use of coal to power datacenters.

Carbon limits for power plants 'suffocate our economy'

The Biden-era carbon emissions rule for power plants, finalized the same day as the mercury rule in April 2024, imposed limits on CO2 emissions from existing coal-fired and new gas-fired power plants. As designed, the rule in effect required operators of coal plants to install carbon capture technology or shut the plants down. The rule drew praise from climate groups but was criticized by electric utilities that said carbon capture retrofits were too expensive and that resulting plant retirements would threaten grid reliability.

The mandates "were enacted seeking to suffocate our economy in order to protect the environment, seeking to make all sorts of industries — including coal and more, disappear," US EPA Administrator Lee Zeldin said in an announcement at the EPA headquarters in Washington, DC, flanked by Republican lawmakers from coal-heavy districts.

Zeldin also said the power plant emissions standards contradicted the Supreme Court's 2022 decision in West Virginia v. EPA, which struck down the Obama administration's Clean Power Plan.

The Supreme Court in that decision held that "the major questions doctrine barred EPA from misusing the Clean Air Act to manipulate Americans' energy choices and shift the balance of the nation's electrical fuel mix." Zeldin said. "In this action, EPA is proposing to define that the 2015 standards for new power plants, [and] the 2024 rule that updated standards for new plants and revised standards for existing power plants also misused the Clean Air Act."

Fossil fuel-fired generators are the nation's largest stationary source of greenhouse gas emissions, accounting for 25% of economywide CO2 emissions in 2022, according to data from the EPA. Under the Biden administration, the agency projected that the emissions limits would result in up to $370 billion in climate and public health net benefits over the next two decades.

The EPA's June 11 rulemaking "seeks to nullify the legal and scientific consensus that carbon dioxide and hazardous pollutants pose grave threats to human and environmental health," Joe Goffman, a former assistant administrator for the agency's Office of Air and Radiation, said in a statement. "Allowing the largest industrial sources of both climate pollution and toxic emissions to operate without restraint would mark a catastrophic failure of environmental protection."

Weakening mercury standards 'indefensible'

The EPA's proposed repeal of the 2024 update to the Mercury and Air Toxics Standards for coal plants comes just weeks after the agency gave more than one-third of the nation's coal fleet a two-year reprieve from the rule. That exemption gave operators time to avoid certain requirements, including a new mandate for plants to install monitors that continuously measure emissions.

The American Lung Association urged the EPA to reconsider its decision to roll back the mercury standards.

"Many power plants were already complying with the Mercury and Air Toxics Standards and the technology is available," the health advocacy group said. "Weakening the standards now is indefensible from a public health standpoint and a betrayal of EPA's mission."

The EPA's updated mercury rule specifically sought to close the so-called lignite loophole, which for years has allowed weaker mercury limits for lignite-fired coal plants. Mercury is a powerful neurotoxin that can stunt the brain development of young children and cause other serious health problems for adults.

In issuing the final mercury rule, the agency said at the time that the regulation reflected advances in pollution control technology and would be expected to prevent 1,000 pounds of mercury emissions in 2028. The rule was also projected to avoid the release of at least 7 tons of other hazardous air pollutant metals, such as nickel, arsenic and hexavalent chromium during the same year.

Some industry observers said it is premature to declare the carbon and mercury rules for power plants a done deal.

"I think passing this proposal will be difficult due to opposition from various groups, including utilities, due to legal, economic, political and procedural bases," Simon Wong, a portfolio manager with Gabelli Funds, said in an email. "I think the final proposal, unless it is hard-coded by the Supreme Court, will likely be diluted."

The EPA is accepting public comments within 45 days of the proposals' publication in the Federal Register.